/**
 * 霍夫圆变换：HoughCircles()
 */

#include <opencv2/imgcodecs.hpp>
#include <opencv2/highgui.hpp>
#include <opencv2/imgproc.hpp>

using namespace cv;
using namespace std;

int main(int argc, char *argv[]) {
    //![load]
    const char *filename = argc >= 2 ? argv[1] : "smarties.png";

    // Loads an image
    Mat src = imread(samples::findFile(filename), IMREAD_COLOR);

    // Check if image is loaded fine
    if (src.empty()) {
        printf(" Error opening image\n");
        printf(" Program Arguments: [image_name -- default %s] \n", filename);
        return EXIT_FAILURE;
    }
    //![load]

    //![convert_to_gray]
    Mat gray;
    cvtColor(src, gray, COLOR_BGR2GRAY);
    //![convert_to_gray]

    //![reduce_noise]
    medianBlur(gray, gray, 5);
    //![reduce_noise]

    //![houghcircles]
    vector<Vec3f> circles;
    HoughCircles(gray, circles, HOUGH_GRADIENT, 1,
                 gray.rows / 16,  // change this value to detect circles with different distances to each other
                 100, 30, 1, 30 // change the last two parameters
            // (min_radius & max_radius) to detect larger circles
    );
    //![houghcircles]

    //![draw]
    for (size_t i = 0; i < circles.size(); i++) {
        Vec3i c = circles[i];
        Point center = Point(c[0], c[1]);
        // circle center
        circle(src, center, 1, Scalar(0, 100, 100), 3, LINE_AA);
        // circle outline
        int radius = c[2];
        circle(src, center, radius, Scalar(255, 0, 255), 3, LINE_AA);
    }
    //![draw]

    //![display]
    imshow("detected circles", src);
    waitKey();
    //![display]

    return EXIT_SUCCESS;
}
